A massive magma reservoir has been detected deep beneath Tuscany, despite showing no obvious signs at the surface. Scientists mapped the roughly 6,000-cubic-kilometer body using natural ground vibrations recorded by dozens of seismic sensors. It poses no immediate danger, but the discovery reveals how enormous volcanic systems can remain hidden and could transform the search for geothermal energy and critical minerals.

Some of the world’s best-known volcanic regions, including Yellowstone National Park in the United States, Lake Toba in Indonesia, and Lake Taupo in New Zealand, sit above magma reservoirs containing thousands of cubic kilometers of molten material.

Scientists usually identify these systems through visible or measurable evidence at the surface. Such clues can include ancient eruption deposits, volcanic craters, rising or sinking ground, and escaping gases. When those signs are absent, however, even enormous quantities of magma can remain undetected within Earth’s crust.

That appears to have happened in Tuscany. Researchers from UNIGE, working with specialists from the Institute of Geosciences and Earth Resources (IGG-CNR) and the National Institute of Geophysics and Volcanology (INGV), mapped approximately 6,000 km3 of volcanic fluids within the continental crust.

The newly identified material extends across Tuscany at depths ranging from 8 to 15 km.

—>Over geological timescales, a magma body of this size could theoretically play a role in the development of a supervolcano. Researchers emphasize, however, that the system does not currently represent a threat.<—

link to open access paper https://www.nature.com/articles/s43247-026-03334-0